MP63-17 EARLY DETECTION OF CLINICALLY SIGNIFICANT PROSTATE CANCER: LOW FREE PROSTATE-SPECIFIC ANTIGEN LEVELS AS A CRITERION FOR PROSTATE BIOPSY IN PATIENTS WITH LOW TOTAL PROSTATE-SPECIFIC ANTIGEN LEVELS

Abstract

INTRODUCTION AND OBJECTIVES: The present study investigated whether applying %fPSA as a criterion for prostate biopsy in patients with low PSA ( 4.0 ng/mL) could facilitate early diagnosis of clinically significant prostate cancer. METHODS: Free prostate-specific antigen (fPSA) levels have been measured in addition to total prostate-specific antigen (PSA) in all patients undergoing prostate cancer screening at Tohoku University and the Miyagi Cancer Society since July 2001. Subjects comprised 9,522 patients who underwent screening for prostate cancer between July 2001 and June 2011. Patients with %fPSA 12% and PSA 2.0 10.0 ng/mL with no gaps in prostate biopsy histopathological diagnosis (n 1⁄4 260) were divided into the following two PSA groups: low (PSA: 2.0 4.0 ng/mL) and mildly elevated (PSA: 4.1 10.0 ng/mL). Malignancy was evaluated based on Gleason scores of biopsy specimens. Statistical significance was assessed using Pearsons c test. RESULTS: Median age, PSA, and %fPSA were 66 years, 4.5 ng/mL, and 9.9%, respectively. A total of 129 patients (49.6%) were diagnosed with prostate cancer based on biopsy of all patients in the low PSA (n 1⁄4 114, 43.8%) and mildly elevated PSA (n 1⁄4 146, 56.2%) groups. No significant differences were observed between the low PSA group and the mildly elevated PSA group (p 1⁄4 0.1010) in prostate cancer detection rate. Patients were then further classified as low, medium, or high risk (Gleason scores 6, 7 and 8 , respectively) based on biopsy histopathological diagnosis. However, no significant differences were observed between the low and mildly elevated PSA groups (p1⁄40.9974) in malignancy. Overall detection rate in the mediumand high-risk patients was 76%, and highlyiimalignant prostate cancer was efficiently detected. CONCLUSIONS: If %fPSA is low, clinically significant prostate cancer is likely to be diagnosed, even in patients with low total PSA. A high detection rate of 76% was achieved in mediumand high-risk patients, demonstrating that highly malignant prostate cancer was efficiently detected. Including %fPSA as a criterion for prostate biopsy could facilitate early diagnosis of clinically significant prostate cancer, even in patients with low total PSA.